Re: Show that the matrix representation of the dihedral group D4 by M is irreducible.

Originally Posted by blueyellow

Show that the matrix representation of the dihedral group D4 by M is irreducible.

You are given that all of the elements of a matrix group M can be generated
from the following two elements,

A=
|0 -1|
|1 0|

B=
|1 0|
|0 -1|

in the sense that all other elements can be written A^n B^m for integer m, n >or= 0.
Find the remaining elements in M.

Alternatively, you could do the second part first (which is trivial) and then (assuming you are talking about -representations) appeal to the common theorem that a representation is irreducible if and only if the inner product of the character with itself is one, i.e. if .